Bolt guard



Aug. 18, 1970 D. E. REID BOLT GUARD Filed May 17, 1968 DONALD E. REID ATTORNEYS United States Patent 3,524,669 BOLT GUARD Donald E. Reid, 647 Broadview Ave., Toronto 6, Ontario, Canada Filed May 17, 1968, Ser. No. 730,012 Int. Cl. Eb 17/00 US. Cl. 292346 11 Claims ABSTRACT OF THE DISCLOSURE To prevent unauthorized entry by the insertion of a flat member between a door and its jamb thereby to force open a spring-loaded sliding bolt, guard members are mounted on the outer side of the bolt, both on the door and on the jamb. These guard members define a labyrinthine seal on the three accessible sides of the bolt. The guard members are in the shape of three-sided frames, one of which is pivotally mounted on the strike plate. Means readily accessible when the door is open are provided for adjusting the position of the latter guard member.

The present invention relates to bolt guards, more particularly of the type adapted to prevent the insertion of a thin member between a door and its jamb so as to force back a spring-loaded sliding bolt.

Unauthorized entry can often be quickly and easily effected by sliding a thin flat and preferably flexible member between a door and its jamb, the advancing edge of the inserted member striking the inclined forward surface of the bolt and urging the bolt to retracted position so that the door can be opened. The flexibility of these insertable members and the skill with which they can be manipulated make it possible for this operation to be conducted despite the fact that guard members as known heretofore are interposed in the path of the inserted member. Moreover, the inserted member can reach the bolt not only from the front but also from above or below.

Therefore, it is an object of the present invention to provide a bolt guard which elfectively blocks the insertion of such a member into contact with the bolt.

Another object of the present invention is the provision of a bolt guard that is quickly and easily adjustable in accordance with the actual distance between the door and its jamb when the door is closed.

Finally, it is an object of the present invention to provide a bolt guard that is relatively simple and inexpensive to manufacture, easy to install in connection with any of a variety of existing closures, and rugged and durable in use.

Other objects and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawing, in which:

FIG. 1 is a clam shell view in perspective, with parts broken away, of a bolt guard assembly according to the present invention;

FIG. 2 is a cross-sectional view on a horizontal plane of the assembly in use in connection with a closed door; and

FIG. 3 is an exploded perspective view of a bolt guard assembly according to the present invention.

Referring now to the drawing in greater detail, there is shown an embodiment of the present invention in use in connection with a closure comprising a door 1 that closes with and against a stationary door jamb 3. Door 1 is provided in an edge portion thereof with a retractible sliding bolt 5 that is spring urged to the extended position of FIG. 1 and that has an inclined front surface,

which is its upper surface as seen in FIG. 2. Of course,

bolt 5 is selectively retractible by means of a lock assembly (not shown). It is against this inclined surface of bolt 5 that a thin and preferably flexible member can be pushed in order to gain unauthorized entry.

Bolt 5 protrudes through a plate 7 secured flush to the edge of door 1 by screws 9.

A strike plate 11 is in the usual position to door jamb 3 by means of screws 13 that extend through upper and lower holes 15 through the ends of the strike plate. Strike plate 11 has an opening 17 through a flat portion thereof, for the reception of bolt 5 in the closed position of the door; and the bolt 5 traverses an inclined tongue 19 on its way to opening 17. Of course, strike plate 11 overlies the usual bolt-receiving mortise in the jamb. A lip 21 is stamped from the material that is removed to form opening 17 and extends inwardly from the plane of the flat portion of strike plate 11. Lip 21 serves to locate the strike plate accurately with respect to the mortise of the door jamb, and also provides an abutment for the rear surface of the bolt.

A guard member 23 in the form of a three-sided frame is carried by strike plate 11. Guard member 23 has a guard portion 25 that is disposed generally upright in the operative position of the parts and perpendicular to the plane of the flat portion of strike plate 11. Guard portion 25 has legs 27 at either end thereof, which are disposed in horizontal planes and are parallel to each other and disposed one above and one below the opening 17 through strike plate 11. Each leg 27 has an enlargement 29 at its free or rear end, and each enlargement 29 extends through a hole 31 in strike plate 11 and is expanded on the inner side of strike plate 11 thereby pivotally to interconnect guard member 23 to strike plate 11 for horizontal swinging movement about a verti cal axis that passes through or closely adjacent both holes 31.

Legs 27 are formed with inwardly extending horizontal fins 33 thereon, that extend through horizontal slots 35 that open through strike plate 11 parallel to each other and that are disposed one above and one below opening 17.

Guard portion 25 is formed with an ear 37 on its innermost edge; and strike plate 11 is formed with an ear 39 that extends over a portion of opening 17 and is disposed in the plane of the fiat portion of strike plate 11. Ears 37 and 39 are parallel to each other and to fiat portion of strike plate 11; and in the assembled position of the parts shown in FIGS. 1 and 2, ears 37 and 39 have openings therethrough that are coaxial. A Screw 41 extends loosely through ear 39 and is screw-threadedly received in car 37 and has its head located generally in the plane of the flat portion of strike plate 11 and exposed in the assembled position of the parts when the door is open, as shown in FIG. 1. A coil compression spring 43 surrounds screw 41 and is in compression between ears 37 and 39 to urge guard member 23 to swing inwardly about the rear ends of its legs 27.

A second frame 45 also forms a portion of the bolt guard assembly of the present invention. Second frame 45 is also a three-sided frame Which, like guard member 23, opens in the direction from which the bolt approaches the closed position of the door. Second frame 45 comprises an upright guard portion 47 from the ends of which extend horizontally a pair of legs 49 that are disposed in horizontal parallel planes. Ears 51 are formed integrally with legs 49 but at right angles thereto, the cars 51 being coplanar and extending in opposite directions from their respective legs 49 and being traversed by holes 53 by which second frame 45 is secured to the door in the posi tion shown in FIG. 1, in which second frame 45 surrounds bolt 5 on three sides with one leg 49 above and the other leg 49 below bolt 5. Second frame 45 is secured to door 1 over plate 7 by means of the same screws 9 that secure plate 7 to door 1, the screws 9 passing through holes 53 and thus pressing ears 51 flat against plate 7.

Second frame 45 thus has generally the same shape as the first frame comprised by guard member 23, except that it is somewhat smaller than guard member 23. In the assembled position of the parts represented by the closed door position of FIG. 2, therefore, second frame 45 is disposed within guard member 23 with its legs 49 closely adjacent and parallel to legs 27 of guard member 23 and its guard portion 47 disposed closely adjacent and on the inner side of guards portion 25 of guard member 23. A labyrinthine seal is thus provided to the front and also on the upper and lower sides of bolt 5, such that a flexible member inserted between the door and its jamb cannot find its Way through this labyrinthine seal to contact and press back the bolt 5.

As the edge of the door may be spaced an unpredictable distance from the confronting surface of the jamb and strike plate, it is desirable that the guard portion 25 be adjustable so that its outermost edge can be spaced farther from or nearer to the plane of the fiat portion of strike plate 11, that is, so that the outer edge of guard portion 25 can be as close as possible to plate 7 on the door without interference. This can be accomplished by manipulation of screw 41, the ear 39 on strike plate 11 remaining stationary and the ear 37 on guard member 23 accordingly moving in or out upon turning of screw 41, thereby to swing guard portion 25 about the ends of legs 27. It is particularly to be noted that the head of screw 41 is always exposed when the door is open, so that this adjustment can be quickly made without any disassembly of the parts. At the same time, the spring 43 continuously maintains the head of screw 41 against the ear 39 thereby to keep the parts from rattling and to maintain the proper position of the parts.

In view of the foregoing disclosure, therefore, it will be evident that all of the initially recited objects of the present invention have been achieved.

Although the present invention has been described and illustrated in connection with preferred embodiments, it it to be understood that modifications and variations may be resorted to without departing from the spirit of this invention, as those skilled in this art will readily understand.

Having described my invention, I claim:

1. A bolt guard comprising a strike plate adapted to be mounted on a stationary portion of a closure, said strike plate having an opening through a fiat portion of the strike plate to receive the bolt of a closure fastener, a guard memberhaving an upright guard portion and a pair of legs at either end of the guard portion by which the guard member is pivotally interconnected with the strike plate, said legs being disposed on opposite sides of said opening and defining with said guard portion a three-sided frame that opens in the direction from which the strike plate receives a bolt and that extends outwardly beyond the plane of said flat portion, and an adjustment member disposed within the area bounded by said threesided frame and acting between the upright guard portion of said frame and said flat portion selectively to alter the pivoted position of the guard member relative to the strike plate.

2. A bolt guard as claimed in claim 1, said adjustment member having a portion exposed for adjustment when the strike plate is installed in operative position adjacent a closure.

3. A bolt guard as claimed in claim 1, and means resiliently urging said frame inwardly behind the plane of said fiat portion.

4. A bolt guard as claimed in claim 3, said adjustment member comprising a screw that engages between said frame and said strike plate, said resiliently urging means comprising a coil compression spring encompassing said screw between said frame and said strike plate.

5. A bolt guard as claimed in claim 1, and a second three-sided frame, said second frame being adapted to be mounted on the movable portion of a closure with a bolt carried by the closure disposed within the second frame, said second frame having an upright guard portion and a pair of legs at either end of the latter guard portion, said second frame being smaller than the firstmentioned frame and being adapted to fit Within said firstmentioned frame in the closed position of the closure with said guard portions of the two frames overlying each other in a direction parallel to the plane of said flat portion of the strike plate.

6. A bolt guard as claimed in claim 1, said three-sided frame extending outwardly beyond the plane of said flat portion in one direction and having an ear thereon that extends inwardly of the plane of said flat portion in the other direction, said adjustment member extending between said flat portion and said ear inwardly of said plane.

7. A bolt guard as claimed in claim 6, said adjustment member comprising a screw whose head engages in said flat portion and whose tail engages screw-threadedly in said ear.

8. A bolt guard comprising a strike plate adapted to be mounted on a stationary portion of a closure, said strike plate having an opening through a fiat portion of the strike plate to receive the bolt of a closure fastener, a guard member having an upright guard portion and a pair of legs at either end of the guard portion by which the guard member is pivotally interconnected with the strike plate, said legs being disposed on opposite sides of said opening and defining with said guard portion a three-sided frame that opens in the direction from which the strike plate receives a bolt and that extends outwardly beyond the plane of said flat portion, said strike plate having holes therethrough behind said legs, said legs having inwardly extending projections thereon that are disposed in said holes, and an adjustment member disposed within the area bounded by said three-sided frame and acting between the upright guard portion of said frame and said flat portion selectively to alter the pivoted position of the guard member relative to the strike plate.

9. A bolt guard as claimed in claim 8, said holes being slots parallel to said legs, said projections being elongated fins disposed in said slots.

10. A bolt guard comprising a strike plate adapted to be mounted on a stationary portion of a closure, said strike plate having an opening through a flat portion of the strike plate to receive the bolt of a closure fastener, a guard member having an upright guard portion and a pair of legs at either end of the guard portion by which the guard member is pivotally interconnected with the strike plate, said legs being disposed on opposite sides of said opening and defining with said guard portion a threesided frame that opens in the direction from which the strike plate receives a bolt and that extends outwardly beyond the plane of said fiat portion, said strike plate having holes therethrough behind said legs, said legs having inwardly extending projections thereon that are disposed in said holes.

11. A bolt guard as claimed in claim 10, said holes being slots parallel to said legs, said projections being elongated fins disposed in said slots.

. References Cited UNITED STATES PATENTS 975,675 11/ 1910 Bumiller 292346 1,781,813 11/1930 Goodwin 292346 1,853,456 4/1932 Ross 292-346 1,919,739 7/1933 Minzenmayer 292346 3,097,008 7/ 1963 Gravelle 292-346 MARVIN A. CHAMPION, Primary Examiner E. J. MCCARTHY, Assistant Examiner 

